Method of providing a mobility service

ABSTRACT

A method comprising running an application on user equipment; providing a mobility service; using a packet switched connection when said mobility service is unavailable; and using said mobility service when said mobility service becomes available.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation application of U.S. patentapplication Ser. No. 14/538,092, filed on Nov. 11, 2014. U.S. Ser. No.14/538,092 is a continuation application of U.S. patent application Ser.No. 13/789,892, filed on Mar. 8, 2013 and which is now U.S. Pat. No.8,914,033. U.S. patent application Ser. No. 13/789,892 is a continuationapplication of U.S. patent application Ser. No. 11/614,906, filed onDec. 21, 2006 and which is now U.S. Pat. No. 8,412,207. U.S. patentapplication Ser. No. 14/538,092, U.S. patent application Ser. No.13/789,892, and U.S. patent application Ser. No. 11/614,906 areincorporated herein by reference.

TECHNICAL FIELD

Various embodiments relate to a method of providing a mobility service,for example mobile IP, and user equipment comprising an application.

BACKGROUND

A communications system is a facility which enables communicationbetween two or more entities such as user terminal equipment and/ornetwork entities as the nodes associated with a communication system.The communication may comprise, for example, communication of voice,electronic mail (email), text messages, etc.

The communication may be provided by a fixed line and/or wirelesscommunication interface. A feature of wireless communication systems isthat they provide mobility for the users thereof. An example ofcommunications systems providing wireless communication are public landmobile networks (PLMN). An example of the fixed line system is a publicswitched telephone network (PSTN).

A communications system typically operates in accordance with a givenstandard or specification which sets out what the various elements ofthe system are permitted to do and how that should be achieved. Forexample, the standard or specification may define if the user, or moreprecisely user equipment, is provided with a circuit switched service ora packet switched service or both. Communication protocols and/orparameters which should be used for the connection also are typicallydefined. For example, the manner in which communication should beimplemented between the user and the elements of the communicationnetwork is typically based on a predefined communication protocol. Inother words, a specific set of “rules” on which the communication can bebased need to be defined to enable to communication.

So-called “multi-homed” mobile devices (user equipment) have beenproposed where IP (internet protocol) connectivity via access networksmay appear and disappear due to mobility of the user equipment. Forexample, a multi-homed user equipment may be arranged to be capable ofaccessing a WLAN (wireless local area network) and a GPRS network(general packet radio service). A WLAN network is generally a localisednetwork, for example run in the context of an office environment whereasthe GPRS network is a public land mobile network. Typically, when theuser equipment is in the office environment it is preferred that theuser equipment accesses the WLAN network but when the user equipmentleaves the office environment the user equipment accesses the GPRSnetwork.

When the user equipment moves for example from the WLAN network to theGPRS network, or vice versa, the user equipment IP (Internet Protocol)address will change. The applications that are running in the userequipment can use a mobility service (such as mobile IP, if the networkinfrastructure is supported) or the application can manage connectionbreaks itself by reconnecting sockets after the moving from one networkto another.

If the user equipment application has chosen to use a mobility service,such as Mobile IP, it may occur that a home agent (HA) is not reachablebecause the HA server is down or for example an internet link betweenthe user equipment and the home agent server is down. This causes aproblem that the applications running on the user equipment will not beable to automatically keep their source IP address unchanged and thesockets unbroken, if for example the user equipment moves from onenetwork to another. Applications using mobile IP make the assumptionthat the mobility service works at all times and do not have the abilityto cope with the problem caused by the home agent being unreachable.This results in a bad user experience.

In more detail, the mobility service, such as mobile IP is normally usedon top of a packet switched connection, such as IP. When the HA serveris not reachable, the mobile IP implementation deactivates itself on thepacket processing path of the user equipment TCP/IP (Transport controlprotocol/Internet Protocol) stack. In this case, the client applicationwas able to continue using an IP connection if it was still working.However, it was not possible for the user equipment to resume thedesired mobility service as it brings a seamless service to UE.Furthermore, because the mobile IP connection is broken, the IP addressof the application was changed resulting in the existing sockets beingbroken without prior notice. This results in a breaking or discontinuityin a service being used by the user equipment.

It is therefore an aim of at least some embodiments to address or atleast mitigate one or more of the problems described.

SUMMARY

According to various embodiments, there is provided a method comprisingrunning an application on user equipment; providing a mobility service;using a packet switched connection when said mobility service isunavailable; and using said mobility service when said mobility servicebecomes available.

According to various embodiments, there is provided a method comprisingproviding an application on user equipment; using a first mobilityservice; and changing to a second packet switched connection mode whensaid first mobility service is unavailable; and changing from onenetwork to another when said first service is unavailable, under thecontrol of said application using said second connection mode.

According to various embodiments, there is provided a user equipmentcomprising an application configured to run on said user equipment; amobility service entity configured to provide a mobility service; saiduser equipment being configured to use a packet switched connection whensaid mobility service is unavailable and to use said mobility servicewhen said mobility service becomes available.

According to various embodiments, there is provided a user equipmentcomprising an application configured to use a mobility service and tochange to a packet switched connection when said mobility service isunavailable, said user equipment being configured to be under thecontrol of said application when said packet switched connection is usedand said user equipment moves from one network to another

According to various embodiments, there is provided a computer readablemedium comprising an application to be run on user equipment, saidapplication configured to control roaming of said user equipment when amobility service is unavailable such that a packet switched connectionis used.

According to various embodiments, there is provided a computer readablemedium comprising a first executable component to cause an applicationto be run on user equipment; a second executable component configured toproviding a mobility service; a third executable component configured tocause a packet switched connection to be used when said mobility serviceis unavailable; and a fourth executable component configured to causesaid mobility service to be used when said mobility service becomesavailable.

According to various embodiments, there is provided a user equipmentcomprising means for running an application on user equipment; means forproviding a mobility service; means for using a packet switchedconnection when said mobility service is unavailable; and means forusing said mobility service when said mobility service becomesavailable.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments will now be explained with reference to theaccompanying drawings in which:

FIG. 1 shows a network environment in which various exemplaryembodiments can be used;

FIG. 2 shows a flow diagram of a method embodying the exemplaryembodiments where a mobility service fails;

FIG. 3 shows a method embodying the exemplary embodiments where thepreviously unavailable mobility service becomes available; and

FIG. 4 shows a block diagram of user equipment embodying the exemplaryembodiments.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

As an example of mobility service, Mobile IP, used in some embodiments,provides an efficient, scalable mechanism for Error! Hyperlink referencenot valid. within the Internet. Using Mobile IP, nodes may change theirpoint-of-attachment to the Internet without changing their IP address.This allows them to maintain transport and higher-layer connectionswhile moving. Node mobility is realized without the need to propagatehost-specific routes throughout the Internet routing fabric.

In brief, Mobile IP works as follows. A mobile node can have twoaddresses—a permanent home address and a care-of address, which isassociated with the network the mobile node is visiting. There are twokinds of entities in Mobile IP:

-   -   A home agent stores information about mobile nodes whose        permanent address is in the home agent's network.    -   A foreign agent stores information about mobile nodes visiting        its network. Foreign agents also advertise care-of addresses,        which are used by Mobile IP.

A node wanting to communicate with the mobile node uses the home addressof the mobile node to send packets. These packets are intercepted by thehome agent, which uses a table and tunnels the packets to the mobilenode's care-of address with a new IP header, preserving the original IPheader. The packets are decapsulated at the end of the tunnel to removethe added IP header and delivered to the mobile node.

When acting as sender, the mobile node simply sends packets directly tothe other communicating node through the foreign agent. If needed, theforeign agent could employ reverse tunneling by tunneling mobile node'spackets to the home agent, which in turn forwards them to thecommunicating node.

FIG. 1 is a highly schematic view of the environment in which exemplaryembodiments can be provided. User equipment 2 can be any suitabledevice. It may for example be a mobile station, a mobile phone, apersonal data assistant, a personal organiser, a portable computer orany other suitable functionality.

The user equipment 2 is able to communicate packet data either via aGPRS network 4 or a WLAN network 6. The GPRS network is for example inaccordance with the 3GPP standards (3^(rd) Generation PartnershipProject). The WLAN network 6 may be in accordance with the WLANstandards 802.11x, or the like.

In the embodiment shown in FIG. 1, both of the networks are packet datanetworks. It should be appreciated that in alternative embodiments, anytwo packet data networks can be used. It should be appreciated that invarious embodiments, the user can move between more than two packet datanetworks and accordingly the user equipment is capable of connecting tomore than two packet data networks. The two packet data networks are notnecessarily different and may be of the same type.

A home agent 8 is part of the user equipment's home network and can beaccessed via the GPRS network 4 or the WLAN network 6. The home agent 8has a binding cache which is able to map various addresses of userequipment. In particular, the home agent makes sure that when the IPaddress of the user equipment 2 changes that any packets intended forthe user equipment can be directed correctly to that user equipment. Thehome agent thus acts as a register with details of an IP address oraddresses of user equipment. The IP addresses may be relatively staticor may change relatively often.

Exemplary embodiments may be used where a mobility service becomesunreachable or becomes reachable. When mobility service is used, theswitching between connections is transparent to applications because themobility service hides the mobility from the applications. When themobility service is not available, the user equipment may need to changeits IP address, close and reopen sockets.

In a packet switched network such as an IP network, if without amobility service, moving of an UE between networks means a connectionbreak and reconnection from the viewpoint of the application. In thepacket switched connection mode, an application can be notified about apreferred connection in order to help it make a decision. In exemplaryembodiments, a mechanism is provided for moving from the mobilityservice mode to the packet switched connection mode and/or vice-versa,depending on the availability of the mobility service.

In various embodiments, a mobility service such as mobile IP is used ontop of a packet switched connection such as IP connection. When the HAis down or a link between the HA and the user equipment is broken, therewill be no mobility service. In various embodiments, when this occurs,the connection is downgraded to a packet switched connection such as anIP connection and then the mobility service is resumed when it isavailable.

Reference is now made to FIG. 4 which schematically shows functionalityof user equipment embodying the exemplary embodiments. The userequipment has an application functionality 10 which uses a mobilityservice functionality 12. The mobility service is effectively partlyimplemented in the user equipment and partly in the network. The networkprovides a service for the user equipment but for an application runningon the user equipment, the user equipment implementation of the mobilityservice, for example mobile IP, can also be regarded as a mobilityservice. For example, the mobile IP protocol requires the home agent (aserver in the network) and mobile IP protocol information for theterminal equipment (UE). In other words, the mobile station needs to beable to support mobile IP.

The application functionality 10 and the mobility service functionality12 are both arranged to use the destination network 14. The destinationnetwork 14 consists of a group of accesses 16 and 18, each accessleading to a certain packet switched network, such as an IP networkproviding a certain set of services. In the embodiment shown in FIG. 4the access consist of a GPRS 16 and a WLAN 18. The accesses are arrangedso that the destination network will have a selection policy parameterin order to determine which of the available accesses are selected. Forexample, one access may be given a priority over another. Alternatively,any other suitable selection policy can be used.

An example of the destination network is a home WLAN, burger WLAN, andoperator GPRS. Each of these accesses leads to the Internet. Besides theissue of the availability of above mentioned accesses, normally aconnection providing higher data rate, e.g. WLAN, may be preferred.

Reference is now made to FIG. 2 which shows a method used in exemplaryembodiments when a mobility service fails.

In step S1, the user equipment application 10 uses the mobility servicefunctionality 12 which is configured to use the destination network. Inthis embodiment, the WLAN access is first used, by way of example. Instep S1, it is assumed that the user equipment is using a mobilityservice, for example mobile IP, via the WLAN. Thus, initially, aseamless service is provided. By seamless, this is meant that theapplication running on the user equipment does not need to react whenthe interface changes. The application sockets do not break and theoperation continues as before. In this way, any breaks in theconnectivity can be minimised. The IP address is unchanged. The mobilityservice, for example mobile IP, is running on top of the packet switchconnection, for example, an IP connection.

In step S2, the HA server or agent 8 is no longer available eitherbecause the Internet via which the home agent is accessed or the homeagent server itself is not working.

In step S3, the user equipment reacts to this. In particular, themiddleware on the user equipment informs the application functionality10 that the mobility service is not available, and that connectionshould be downgraded to WLAN connection and the service type is nownon-seamless. In other words, the access is unchanged but the servicetype is changed to non-seamless. Non-seamless means that the applicationfunctionality needs to react because the terminal IP address may change,the sockets may be closed and reopened. The application functionality 10closes and reopens its socket because of the change in its source IPaddress. There is therefore no mobility service any more and theconnection is downgraded to a packet switched connection such as an IPconnection.

Middleware is the software that runs on the user equipment. Theapplications use middleware and middleware uses hardware dependentsoftware.

In step S4, a determination is made as to whether or not the user hasmoved to a GPRS coverage area. If the user does not move, then the userequipment continues to operate as described in relation to step S3. Ifnot, the next step will be step S5.

If the user moves to a GPRS coverage area, the next step is step S5. Theuser equipment will switch to GPRS if the user equipment moves out ofthe WLAN coverage area. As the mobility service is unavailable, theapplication functionality is required to intervene. The applicationfunctionality is signalled that it needs to take action to move to theGPRS system. For example, in an exemplary embodiment, the applicationfunctionality 10 automatically inherits the destination network (i.e.the access for the GPRS network) from the mobility service functionalitythat it is to use. The destination network is a group of accesses thatcan be used to access a certain service. The mobility service handlesmobility between different networks. If a mobility service, for examplemobile IP, suddenly becomes unreachable, then the client application'sdata connection inherits the destination network that the mobilityservice, for example mobile IP, were managing. That way application canbe notified directly when change happens in its connection environment,e.g. when a more preferable access becomes available (if the mobilityservice, for example mobile IP, was available, it would have handled thechange of network, but because it has become unreachable, theapplication has to do it). The connection is still a packet switchedconnection such as an IP connection.

In the case where the user equipment stays within the WLAN coverage, theuser equipment functions as described in relation to step S3 and doesnot progress to step S5. Thus the user equipment will stay with the WLANaccess network,

It should be appreciated, that in some embodiments, that WLAN and GPRSboth provide the user equipment with a mobility service, for examplemobile IP, on top of the packet switched connection such as an IPconnection. Thus the scenario set out in FIG. 2 can be replaced with theUE initially using a GPRS connection in step S1, with a seamless servicebeing provided. In other words a mobility service can be providedinitially by the GPRS network in step S1. In this alternative scenario,in step S5, the UE can move from the GPRS area to the WLAN area. Theaccess networks are by way of example only.

FIG. 3 shows an embodiment where following the scenario discussed inrelation to FIG. 2, the mobility service is available again in otherwords, a connection to the HA server is once again available or the HAserver itself is available.

In step T1, the user equipment is operating in a non-seamless manner andis for example connected to GPRS. The connection used is thus the packetswitched connection such as an IP connection. However, the userequipment may be connected to WLAN as outlined in the alternativescenario above. Depending on the scenario, the service used step T1corresponds to that of step S3 or step S5

In step T2, the HA server in the network is up.

In the terminal there is a periodic timer. FIG. 4 describes therelationship between entities inside phone. The Mobility Servicefunctionality 12 contains the implementation of mobility service (i.e.mobile IP). The timer is for example started when it is determined thatthe HA server is not available. Once the timer has expired, the userequipment tried to reconnect again to the HA. In this embodiment shownin FIG. 3, the HA server is now available. Otherwise, the periodic timeris reset and will count down a predetermined amount of time and step T3will be repeated. Thus in some embodiments, step T3 will follow directlyafter step T1, where the HA server is for example still unavailable. Themethod will progress to step T4 only when a connection has been made tothe HA server.

In step T4, the middleware informs the application functionality thatthe mobility service access is again preferred.

The application functionality signals the middleware to resume amobility service when there is a suitable moment for the applicationfunctionality. After the mobility service is resumed, the applicationcloses and reopens its socket because the source IP address changes. Inother words, mobility service, for example mobile IP, on top of theswitched packet connection, that is the IP connection is again used.

It is checked in step T5 if the user returns to the area of the WLANcoverage from the GPRS coverage area. If so the next step is T6. Themobility service automatically changes the application sockets to theWLAN access without application intervention or changing IP address.

In the case where the user equipment remains in the GPRS coverage area,with no WLAN coverage being available, no application intervention isrequired. In other words the method remains at step T4.

In the alternative scenario, where the user is in the WLAN coveragearea, the user may return to the GPRS coverage area although WLAN may begenerally preferred as it normally offers higher data rate.

Exemplary embodiments may include an additional step of finding anavailable access. This can be carried out prior to, for example, stepS1. This step may additionally or alternatively be carried out when theuser equipment moves out of range of one coverage area or when thesignal strength falls below a given value.

Thus, exemplary embodiments provide a way to preserve applicationconnectivity and mobility where a mobility service fails. A way ofproviding a return to seamless service is also described. Reference ismade to the code below which describes the logic used by the userequipment to inform the application functionality on changes in themobility protocol registration status and allowing a smooth adaptationto changes.

Middleware implementation in pseudo code: IF(mobile IP instance isregistered to HA) {  IF(home registration fails after retrying multipletimes)  {   DowngradeAll( );  } } ELSE {  IF(home registration succeeds) {   UpgradeAll( );    }  ELSE  {   TryAgainAfterTimeout;  } } FUNCTIONDowngradeAll( ) {  FOR (each connection handle i in every application) {   IF(i uses the particular mobility service)   {    Associate i withmobility service's DN;    Run signalling procedure with i so that thebest    access of the DN is selected for i;   }  } } FUNCTIONUpgradeAll( ) {  FOR (each connection handle i in every application)  {  IF(i originally used the particular mobility service)   {    Runsignalling procedure with i so that the    mobility service is againassociated with i;   }  } }

This can be summarised if the user equipment is registered to the homeagent and the home registration fails after trying a predeterminednumber of times (predetermined number of times can be one or more) thenthere is a downgrade to the non-seamless type of service, that is to apacket switched connection such as IP connection. On the other hand, ifthe home registration succeeds then there is an upgrade to the seamlessoperation (see step T4 of FIG. 3) enabled by mobility service running ontop of the packet switched connection.

The possibility of retrying after a timeout period is also given if thehome registration is not successful.

For the downgrade function, for each connection handled in everyapplication, it is determined if the particular connection handle usesthe particular mobility service. If so, the particular connection handleis associated with a mobility services destination network. A signallingprocedure is run for the particular connection handle so that the bestaccess of the destination network is selected for the particularconnection handle.

For the upgrade function, for each connection handle in everyapplication, if a given connection handle is originally using aparticular mobility service, then the signalling procedure for theconnection handle is run so that the mobility service is againassociated with a particular connection handle.

Exemplary embodiments are particularly advantageous in that connectivityand mobility is preserved and the end user's seamless experience may beimproved. The seamless service may be easier to deploy because theapplications are often offered mechanisms to adapt to real lifesituations. Because all application react in a similar way and no ad hocproblem solution attempts are implemented in the applications, exemplaryembodiments may mean that the system overall behavior may be easier topredict.

Exemplary embodiments may be particularly advantageously used in moreintelligent devices such as smart phones and PDA devices. However,exemplary embodiments are not limited to such applications.

Exemplary embodiments can be included in any suitable network inaccordance with any appropriate standard. Exemplary embodiments may forexample be implemented in the mobile IP standards proposed by the IETF(internet engineering task forces) the MobIke standard, WLAN technologyand 3GPP standards.

In exemplary embodiments, the home agent may be replaced by any othersuitable entity. For example, with the MobIke standard, thecommunication may be instead with a VPN gateway.

Exemplary embodiments can also be applied in the context of the firstsession opening. In that way, the application would get knowledge of theconnection as originally based on mobility service such as mobile IP ornot, in other words whether it should handle the connections by itselfor not. Thus in exemplary embodiments, the application running on theuser equipment implements a signalling protocol and reacts according toit. This also occurs after the first connection has been established.

An advantage of exemplary embodiments is that there is earlierinformation of a lost connection from the middle layer so that theapplication does not need to wait for a lost TCP session message orsimilar.

It should be appreciated that various embodiments can be implemented atleast partly by a computer program.

Although described in the context of particular embodiments, it will beapparent to those skilled in the art that a number of modifications andvarious changes to these teachings may occur. Thus whilst the variousembodiments have been particularly shown and described with respect toone or more preferred embodiments thereof, it will be understood bythose skilled in the art that certain modifications or changes, in formand shape, may be made therein without departing from the scope andspirit of exemplary embodiments as set forth above.

The invention claimed is:
 1. A method, comprising: executing anapplication at user equipment, the executing comprising accessing anInternet Protocol (IP) network via a first access using a first IPaddress maintained by a home point-of-attachment, with communications tothe user equipment via the first IP address routed from the homepoint-of-attachment to a foreign point-of-attachment in communicationwith the user equipment; responsive to loss of the homepoint-of-attachment, notifying the application of said loss; thencontinuing the executing of the application, the continued executioncomprising: accessing the IP network via the first access using a secondIP address; and responsive to loss of availability of the first access,accessing the IP network via a second access; responsive to restorationof the home point-of-attachment, notifying the application of saidrestoration; and then continuing the executing of the application, thecontinued execution comprising accessing the IP network using an IPaddress maintained by the home point-of-attachment, with communicationsto the user equipment being routed from the home point-of-attachment toa foreign point-of-attachment in communication with the user equipment.2. The method of claim 1, wherein the first access is wireless localarea network (WLAN) and the second access is general packet radioservice (GPRS).
 3. The method of claim 1, wherein the first access isGPRS and the second access is WLAN.
 4. The method of claim 1, furthercomprising: during the accessing of the IP network using a second IPaddress, periodically trying to reconnect to the homepoint-of-attachment.
 5. The method of claim 1, wherein the step ofexecuting the application at the user equipment further comprises: usinga Mobile IP mobility service to access the IP network via the firstaccess using the first IP address maintained by the homepoint-of-attachment; wherein the home point-of-attachment is a homeagent under the Mobile IP mobility service and the foreignpoint-of-attachment is a foreign agent under the Mobile IP mobilityservice.
 6. The method of claim 1 wherein each of the homepoint-of-attachment and the foreign point-of-attachment is a VPN gatewayunder the Moblke standard.
 7. A user equipment apparatus configured to:execute an application at user equipment to access an Internet Protocol(IP) network via a first access using a first IP address maintained by ahome point-of-attachment, with communications to the user equipment viathe first IP address routed from the home point-of-attachment to aforeign point-of-attachment in communication with the user equipment;responsive to loss of the home point-of-attachment, notify theapplication of said loss; then cause the application to access the IPnetwork via the first access using a second IP address; following thenotifying of the application of said loss and responsive to loss of theavailability of the first access, accessing the IP network via a secondaccess; responsive to restoration of the home point-of-attachment,notify the application of said restoration; and then cause theapplication to access the IP network using an IP address maintained bythe home point-of-attachment, with communications to the user equipmentbeing routed from the home point-of-attachment to a foreignpoint-of-attachment in communication with the user equipment.
 8. Theapparatus of claim 7, wherein the first access is wireless local areanetwork (WLAN) and the second access is general packet radio service(GPRS).
 9. The apparatus of claim 7, wherein the first access is GPRSand the second access is WLAN.
 10. The apparatus of claim 7, wherein theapparatus is further configured to: during the accessing of the IPnetwork using a second IP address, periodically try to reconnect to thehome point-of-attachment.
 11. The apparatus of claim 7, wherein theexecuting of the application also uses a Mobile IP mobility service toaccess the IP network via the first access using the first IP addressmaintained by the home point-of-attachment.